The invention relates to a valve housing.
A housing for gate valves is known from the German Auslegeschrift 15 50 613 and is made of sheet metal shells. The housing shells in this known structure are shaped from sheet metal so that they are hinged to one another and merge seamlessly at the bottom of the housing. After shaping, the housing shells are bent up about the longitudinal axis of the housing chamber and are welded to each other at the abutting edges. Such a manufacturing method allows the disadvantageous weld seam in the bottom of the housing to be eliminated; however, this method is very expensive because of the additional bending procedure.
It is also known to so design a valve housing assembled from hemispherical shells that the weld seam connecting the two shell portions to one another is located in a plane which intersects the transverse and longitudinal axes of the valve (Sulzer technical bulletin, February 1973). In this known housing, which is associated with a low-pressure regulating valve, the weld seam runs around the entire housing without any breaks and without crossing another weld seam. In addition to connecting the housing shells, such weld seam also secures a part carrying the valve seat. This housing design, which is advantageous from as regards welding, has been used in a similar form for a ball cock housing (German Offenlegungsschrift 23 47 825).
The hemispherical shells employed in the known valve housings constitute only the central portion of the housing which must be completed on the sides with tubular stubs. Two additional weld seams must be provided for these tubular stubs which, for connection to a pipe, are equipped with a flange or are designed to be welded. Additional weld seams are formed when a housing mount or an intermediate floor is necessary to complete the valve.